KR20000051531A - Metnod for the preparation of the anisotropic conductive film - Google Patents

Abstract

PURPOSE: A preparation of producing of an anisotropic conductive film is provided which has excellent stability in spite of being exposed at room temperature for a long time by separating a resin component having epoxy group, a resin component helping the film is formed and conductive particle with a curing agent to make two film layer. CONSTITUTION: A process comprise steps of: preparing a first layer of the anisotropic film which dissolving a resin helping a film is formed in a solvent such as methylethylketone and adding a curing agent and a conductive particle, followed by coating on one anisotropic PET film to make shape of the film 15 to 40 micrometer thick; preparing a second layer of the anisotropic film which dissolving a resin helping a film is formed and an epoxy resign in a solvent and being dispersed a conductive particle, followed by coating on another anisotropic PET film to make shape of the film 15 to 40 micrometer thick; and being bonded the first layer of the anisotropic film to the second layer of the anisotropic film. On the other hand, the anisotropic conductive film is obtained by coating the first layer of the anisotropic conductive on a anisotropic PET film, followed by coating the second layer of the anisotropic film is sequentially reiterated. Thereby, the anisotropic conductive film is stable at room temperature and is able to connect ITO with TAB at short time.

Description

Manufacturing method of anisotropic conductive film {METNOD FOR THE PREPARATION OF THE ANISOTROPIC CONDUCTIVE FILM}

The present invention relates to a method for producing an anisotropic conductive film having excellent storage stability, and more particularly to a method for producing an anisotropic conductive film having excellent storage stability at room temperature.

At present, as the resolution and colorization of the liquid crystal display device progress, reduction of pixel pitch (currently commercialized to 50 μm, distance from one pad to the next pad of the microcircuit ITO deposited on the liquid crystal display panel) and There is a trend that the number of leads printed on the liquid crystal display panel is increasing. Due to such technical requirements, a liquid crystal display packaging technology for connecting a liquid crystal display panel, a driver integrated circuit, and a printed circuit board has been developed correspondingly. As circuits become more miniaturized, the packaging technology is also being developed in various ways. Particularly, among the liquid crystal display packaging technologies, the most commonly used method is to pack electrical connection between a liquid crystal display panel and a printed circuit board using a tape-automated bonding (TAB) IC by a chip-on-film (COF) method. In addition, the next-generation liquid crystal display device packaging method is to connect the driver IC bare chip directly to the liquid crystal display panel by IC connection method, and to connect the printed circuit board to an anisotropic conductive film (ACF) using FPC. Law is being used.

The anisotropic conductive film used as the connecting material in the liquid crystal display device packaging described above means a Z-axis conductive adhesive film prepared by dispersing the conductive fine particles in the adhesive and coating it on a release treated PET film in the form of an adhesive film, xy It has insulation in the planar direction. Such anisotropic conductive film has been manufactured by Hidachi Hwaseong Co., Ltd. in Japan for the past 10 years (Japanese Patent Laid-Open Publication Nos. 5-21094, 5-226020, 7-302666, 7-302667, 7-302668, etc.) and Sony. Chemicals (JP-A-7-211374, 8-311420, 9-199206, 9-199207, 9-31419, 9-63355, 9-115335, etc.) Many studies have been conducted, but the storage stability at room temperature is still a lot of improvement is required.

In the present invention, when the resin component having an epoxy group, the resin component which helps to form the film, and the conductive particles are separated from the curing agent component to make two film layers, the curing reaction does not occur before the high temperature and high pressure compression process, so that when exposed at room temperature for a long time An object of the present invention is to obtain an anisotropic conductive film having excellent storage stability.

The anisotropic conductive film according to the present invention is used to connect a transparent electrode (ITO) terminal formed on a substrate of a liquid crystal display device and a copper wiring electrode (TAB) terminal of an external driving circuit. That is, the anisotropic conductive film is a film in which metal particles or particles coated with metal are dispersed in an epoxy insulating adhesive, and are used for connection between two wiring patterns such as a liquid crystal display device and an external driving circuit.

To this end, the liquid crystal display panel substrate and the external driving circuit board (TAB or FPC) are bonded to each other, and then heated and pressurized to cure the thermosetting resin, while the metal particles are constrained between the wiring patterns on both sides of the panel to prevent electrical connection. Is done. In this case, fast curing reactivity is required in order to connect within a short time, but the conventional anisotropic conductive film has a problem that the curing proceeds for a certain elapsed time until the panel connection process after manufacture, but in the present invention can be connected for a short time, even at room temperature An adhesive with excellent long-term storage stability is provided.

This adhesive consists of a resin component having an epoxy group, a resin component which assists in film formation, a curing agent component and a curing accelerator.

As the epoxy resin component, a polyvalent epoxy resin having two or more epoxy groups in one molecule is preferably used. Specific examples include polyhydric phenols such as phenol novolac and cresol novolac novolac resins, bisphenol A, bisphenol F, bishydroxyphenyl ether, ethylene glycol, neopentyl glycol, glycerin, trimethylolpropane, polypropylene glycol, and the like. Polyhydric alcohols, polyamino compounds such as ethylenediamine, triethylenetetraamine, and aniline, polyhydric carboxyl compounds such as phthalic acid and isophthalic acid, and various other aliphatic and aromatic epoxy resins, and the like, alone or two You may mix and use more than that.

In addition, as a resin to assist film formation, a resin that can form a film well without chemically reacting with a selected curing agent is used. Specific examples include acrylic resins such as acrylate resins, ethylene acrylate copolymers and ethylene acrylic acid copolymers, olefin resins such as ethylene resins and ethylene propylene copolymers, butadiene resins, acrylonitrile butadiene copolymers and styrene butadiene blocks. Rubbers such as copolymers, styrene butadiene styrene block copolymers, nitrile butadiene rubber, styrene butadiene rubber, and chloroprene rubber; vinyl resins such as vinyl butyl resin and vinyl form resin; and esters such as polyester and cyanate ester resin. In addition to resins, there are phenoxy resins, silicone rubbers, urethane resins, and the like, and these may be used alone or in combination of two or more thereof.

In addition, as a hardening | curing agent component, if it has two or more active hydrogens in 1 molecule, it can be used. Specific examples include imidazole series, isocyanate series, amine series, amide series, and acid anhydride series, and these may be used alone or in combination of two or more thereof.

On the other hand, the conductive particles used in the present invention are metal particles, inorganic or organic particles coated with a metal, particles having a particle size of several μm can be used, but the size of the particle size is not particularly limited and is arbitrary. Specific examples thereof include metal particles such as Fe, Mn, Zn, Au, Ag, Ni, and particles coated with the metal on the surface of the resin particles, and these may be used alone or in combination of two or more thereof.

The anisotropic conductive film produced by the manufacturing method according to the present invention is manufactured in a two-layer structure using the above components.

The first layer of the anisotropic conductive film consists of a resin, a curing agent, and conductive particles to assist in film formation. That is, the resin assisting the film formation is dissolved in a suitable solvent such as methyl ethyl ketone (MEK) to control the solid content, and the curing agent and the conductive particles are added in an appropriate amount, and then 15 to 40 μm on the release PET film to form the film. To the thickness of the coating.

The second layer of the anisotropic conductive film is coated with a thickness of 15-40 μm on a separate release PET film to form a film by dissolving the resin and the epoxy resin in the solvent to control the solid content and then dispersing the conductive particles. do.

By bonding the first layer and the second layer made as described above can be produced an anisotropic conductive film of a two-layer structure.

On the other hand, after coating the first layer on the release PET film, it is also possible to make an anisotropic conductive film by coating the second layer continuously overlapping.

When the anisotropic conductive film prepared as described above is sandwiched between the liquid crystal display panel panel and the external driving circuit board and bonded by heating and pressing, the resin of the first layer and the second layer is melted and mixed with each other. The curing agent and the epoxy resin of the second layer cause a curing reaction. Below the melting temperature, since the curing agent of the first layer and the epoxy resin of the second layer are not mixed with each other, the two layers can be separated from each other. Reproducibility can be maintained even when exposed in the air.

<Example 1>

After dissolving phenoxy resin (90% by weight) and curing agent 2-methylimidazole (7% by weight) in a mixed solution of toluene and methyl ethyl ketone, conductive particles having a particle size of about 5 μm (Ni plating, 3% by weight) ) Was well dispersed and then coated on a release PET film to make a film A having a thickness of 10㎛.

Next, bisphenol A type epoxy resin (epoxy equivalent 200, 70% by weight) and phenoxy resin (30% by weight) were dissolved in a solvent and coated on a release PET film in the same manner to make a film B having a thickness of 10 μm.

Each heat of cure is measured immediately after preparing this sample and after being left to stand at room temperature for 30 days. Likewise, each sample was sandwiched between the ITO electrode and the TAB electrode, and heated and pressurized at 15 kg / cm 2 for 20 seconds at 170 ° C., and then the adhesiveness and electrical resistance were measured.

<Example 2>

Resin assisted film formation, a mixture of phenoxy resin (50% by weight) and acrylic resin (50% by weight) relative to the phenoxy resin (100% by weight) in Example 1, the rest is the same as in Example 1 It was done.

<Example 3>

As a curing agent, a mixture of diphenyldiaminesulfone (200% by weight) and 1-dodecylimidazole (20% by weight) based on 2-methylimidazole (100% by weight) in Example 1 was carried out. It carried out similarly to Example 1.

<Example 4>

The two layers prepared in Example 1 were used to continuously coat the B layer on the A layer without laminating the layers by lamination.

Example 5

Instead of coating the two layers prepared in Example 2 by lamination, a method of continuously coating the B layer on the A layer was used.

<Example 6>

Instead of coating the two layers prepared in Example 3 by lamination, a method of continuously coating the B layer on the A layer was used.

Comparative Example 1

It did not separate into two layers like Example 1 and Example 4, but was made from the film which consists of one layer from the beginning. That is, it was coated with one layer.

Comparative Example 2

It did not separate into two layers like Example 2 and Example 5, but was made into the film comprised from one layer from the beginning. That is, an anisotropic conductive film is made into one film from the beginning without separating into two layers. To this end, bisphenol A type epoxy resin (epoxy equivalent 200, 40% by weight) and phenoxy resin (50% by weight) are dissolved in a solvent, and 2-methylimidazole (7% by weight) is added thereto as a curing agent to conduct the same. Particles (Ni plating, particle size 5㎛, 3% by weight) was well dispersed and dried to make a film F having a thickness of 20㎛.

Comparative Example 3

It did not separate into two layers like Example 3 and Example 6, but was made from the film which consists of one layer from the beginning.

As described above, the change in the resistance value and the change in calorific value at the time of thermal curing of the anisotropic conductive films prepared according to the examples and the comparative examples, which were observed immediately after the manufacture and stored at room temperature for 30 days, are shown in Table 1 below. Shown in

Resistance value (Ω / □) Curing calorific value (J / g) Right after manufacturing After 30 days left Right after manufacturing After 30 days left Example 1 0.8 1.0 232 231 Example 2 0.7 1.1 232 228 Example 3 0.8 0.9 217 218 Example 4 0.8 0.9 235 202 Example 5 0.7 1.1 230 210 Example 6 0.8 0.9 224 196 Comparative Example 1 0.7 0.8 230 81 Comparative Example 2 0.7 0.8 229 65 Comparative Example 3 0.8 0.8 225 78

As can be seen in Table 1, when comparing the resistance value and the curing calorific value immediately after the manufacture and left for 30 days at room temperature, there is almost no difference in the examples, while the comparative example shows a sharp difference. In addition, in Examples 4 to 6, when the second layer was coated on the film A, the solvent partially penetrated the film A, the curing agent was mixed with the epoxy, and some of the curing reactions resulted in storage stability at room temperature than in Examples 1 to 3. It can be seen that this falls.

According to the manufacturing method of the anisotropic conductive film excellent in the storage stability according to the present invention configured as described above, by separating the epoxy resin and the curing agent into two layers, respectively, and then laminated them, excellent storage stability at room temperature, and thus excellent electrical reliability Can be secured.

Claims (1)

Preparing a first layer by dissolving a resin helping film formation in a suitable solvent to control solid content, adding a curing agent and conductive particles in an appropriate amount, and coating the release PET film to a thickness of 15 to 40 μm; Preparing a second layer by coating a resin having a thickness of 15 to 40 μm on a separate release PET film by dissolving the conductive particles by dissolving the resin and the epoxy resin in a solvent to control solid content, and then dispersing the conductive particles; And, The method of manufacturing an anisotropic conductive film comprising the step of making an anisotropic conductive film of a two-layer structure by laminating the first layer and the second layer to each other.